Fig. 2

Angle definitions. a: The local set of orthogonal planes for the assessment of cardiomyocyte orientation. The plane A is the local epicardial tangential plane. Plane B is the radial-longitudinal plane parallel to the left ventricular long axis and orthogonal to plane A. Plane C is defined as the plane spanned by normal of plane A and the local epicardial horizontal (short axis) tangent. b: The helical angle (blue) is defined as the angle between the cardiomyocytes (yellow rod) and plane C. The transmural angle (green) is defined as the angle between the cardiomyocytes and the epicardial tangential plane A. The E3-angle (yellow) is defined as the angulation between the normal (N) of the aggregate plane (box) and the epicardial tangential plane A. A three-dimensional rotatable 3D PDF of panel b can be found in the supplementary material as Additional file 1